scholarly journals A Molecular-Dynamics Study of Size and Chirality Effects on Glass-Transition Temperature and Ordering in Carbon Nanotube-Polymer Composites

2016 ◽  
Vol 25 (6) ◽  
pp. 571-581 ◽  
Author(s):  
Marcello Malagù ◽  
Alexey Lyulin ◽  
Elena Benvenuti ◽  
Angelo Simone
Keyword(s):  
Molecular Dynamics ◽  
Glass Transition ◽  
Carbon Nanotube ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Polymer Composites

Influence of Carbon Nanotube Aspect Ratio on Glass Transition Temperature of Polymers: A Molecular Dynamics Simulation Study

2015 ◽  
Vol 817 ◽  
pp. 797-802 ◽  
Author(s):  
Cai Jiang ◽  
Jian Wei Zhang ◽  
Shao Feng Lin ◽  
Su Ju ◽  
Da Zhi Jiang
Keyword(s):  
Molecular Dynamics ◽  
Glass Transition ◽  
Carbon Nanotube ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Aspect Ratio ◽  
Epoxy Resin ◽  
Md Simulations ◽  
Diglycidyl Ether ◽  
Dynamics Simulation

Molecular dynamics (MD) simulations on three single walled carbon nanotube (SWCNT) reinforced epoxy resin composites were conducted to study the influence of SWCNT type on the glass transition temperature (Tg) of the composites. The composite matrix is cross-linked epoxy resin based on the epoxy monomers bisphenol A diglycidyl ether (DGEBA) cured by diaminodiphenylmethane (DDM). MD simulations of NPT (constant number of particles, constant pressure and constant temperature) dynamics were carried out to obtain density as a function of temperature for each composite system. The Tg was determined as the temperature corresponding to the discontinuity of plot slopes of the densityvsthe temperature. In order to understand the motion of polymer chain segments above and below the Tg, various energy components and the MSD at various temperatures of the composites were investigated and their roles played in the glass transition process were analyzed. The results show that the Tg of the composites increases with increasing aspect ratio of the embedded SWCNT

Glass transition temperature of functionalized graphene–polymer composites

2013 ◽  
Vol 71 ◽  
pp. 66-71 ◽  
Author(s):  
Qingzhong Xue ◽  
Cheng Lv ◽  
Meixia Shan ◽  
Hongxin Zhang ◽  
Cuicui Ling ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Polymer Composites ◽  
Functionalized Graphene

Free, partial, and fully constrained recovery analysis of cold-programmed shape memory epoxy/carbon nanotube nanocomposites: Experiments and predictions

2018 ◽  
Vol 29 (10) ◽  
pp. 2164-2176 ◽  
Author(s):  
R Abishera ◽  
R Velmurugan ◽  
KV Nagendra Gopal
Keyword(s):  
Glass Transition ◽  
Carbon Nanotube ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Shape Memory ◽  
Thermally Activated ◽  
Large Structures ◽  
Multi Walled Carbon Nanotube ◽  
Optical Strain Measurement ◽  
Optical Strain

Thermally activated shape memory polymers are typically programmed by initially heating the material above the glass transition temperature ( Tg), deforming to the desired shape, cooling below Tg, and unloading to fix the temporary shape. This process of deforming at high temperatures becomes a time-, labor-, and energy-expensive process while applying to large structures. Alternatively, materials with reversible plasticity shape memory property can be programmed at temperatures well below the glass transition temperature which offers several advantages over conventional programming. Here, the free, partial, and fully constrained recovery analysis of cold-programmed multi-walled carbon nanotube–reinforced epoxy nanocomposites is presented. The free recovery analysis involves heating the temporary shape above Tg without any constraints (zero stress), and for fully constrained recovery analysis, the temporary shape is held constant while heating. The partially constrained recovery behavior is studied by applying a constant stress of 10%, 25%, and 50% of the maximum recovery stress obtained from the completely constrained recovery analysis. The samples are also characterized for their thermal, morphological, and mechanical properties. A non-contact optical strain measurement method is used to measure the strains during cold-programming and shape recovery. The different recovery behaviors are analyzed by using a thermo-viscoelastic–viscoplastic model, and the predictions are compared with the experimental results.

Conformational analysis and molecular dynamics of glass-forming aromatic thiacrown ethers

2020 ◽  
Vol 22 (32) ◽  
pp. 17948-17959
Author(s):  
Hubert Hellwig ◽  
Andrzej Nowok ◽  
Jan Grzegorz Małecki ◽  
Piotr Kuś ◽  
Agnieszka Jędrzejowska ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Glass Transition ◽  
Transition Temperature ◽  
Dielectric Properties ◽  
Glass Transition Temperature ◽  
Conformational Analysis ◽  
Ring Type ◽  
Glass Forming ◽  
Thiacrown Ethers

The dielectric properties, glass transition temperature and molecular dynamics of thiacrown ethers are strongly dependent on the thiacrown ring type.

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